Upgrade project.pbxproj to include flutter_assets (#13011)
Upgrade project.pbxproj to include flutter_assets (#13011)


cbracken/flutter,Hixie/flutter,tvolkert/flutter,cbracken/flutter,Hixie/flutter,flutter/flutter,cbracken/flutter,tvolkert/flutter,Hixie/flutter,flutter/flutter,tvolkert/flutter,Hixie/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter,cbracken/flutter,flutter/flutter,tvolkert/flutter,tvolkert/flutter,cbracken/flutter,flutter/flutter,Hixie/flutter,Hixie/flutter,tvolkert/flutter,cbracken/flutter,flutter/flutter,tvolkert/flutter,Hixie/flutter,Hixie/flutter,cbracken/flutter,flutter/flutter,flutter/flutter,cbracken/flutter,Hixie/flutter,flutter/flutter,Hixie/flutter,tvolkert/flutter,flutter/flutter,cbracken/flutter,flutter/flutter